Production of aliphatic di-ketones



Patented Nov. 13, 1951 \PATEN T OFFICE I 1 PRODUCTION OF ALIPHATICDI-KETVONEVSV Edwin George Edward Hawkins, Lower Kingswood, Tadworth,England, assignor to The Distillers Company Limited, Edinburgh,Scotland,

a British company No'Drawing. Application A ril5, 1949, Serial No.85,709. In Great Britain April 29, 1948 The present invention is for aprocess for producing aliphatic di-ketones, in particular long chaindi-ketones, and their derivatives bythe treatment of peroxidiccompounds, and to compounds produced thereby.

It is known that hydroperoxides on reacting with ferrous sulphateyieldketones. Hook and Lang have described in Ber. 75 (1 942) 1 51 and Ber.'76 (1943) 1130 that the hydroperoxides of, indane and octahydroanthracene react when heated with aqueous ferrous sulphate solutionand are decomposed catalytically with the formation of ketones whichpossess the same number; of carbon atoms. The same applies toethylbenzene hydroperoxide which yields acetophenone on being heatedwith an aqueous ferrous sol-- phate solution (ibidern 76 (1943) 172).

It has now been discovered in accordance with this invention thathydroperoxides of compounds wherein the peroxide group is attached to atertiary carbon atom, which forms part ,ofthe saturated alicyclichydrocarbon ring of cyclopentane or cyclohexane and at the same time. is

linked to an alkyl group attached to said ring,

react with ferrous compounds with the production of di-ketones. Fissionof the linkage between the tertiary carbon atomand an adjacent carbonatom in the ring takes place and at the same time identical radicalslink up together so' that di-ketones with double the. number of carbonatoms in the molecule are formed. The following formula for methylcyclopentane hydro-- peroxide illustrates the reaction occurring:

0 onaaLqoHcr -cn.

The principal object of the invention is to produce a simple process forthe production of such di-ketones and to produce useful productsthereby. A I

The invention accordingly comprises the novel products as well as thenovel processes and steps of processes according to which such productsare manufactured, the specific. embodiments of which are describedhereinafter by way of ex;- ample and in accordance, with which it is nowpreferred to practice the invention. 7

6 Claims. ((21.2'60-593) 2 reacting with a solution of a ferrous salt ahydroperoxide of an alkyl substituted alicyclic hydro-v carbonringselected from the group consisting off cyclopentane and cyclohexanewherein the peroxide group is attachedto a tertiary carbon atom.

which forms part of said hydrocarbon ring andwhich is also attached tosaid alkyl group, the. di-ketones produced having twice as many car- Dobon atoms as the said ring compound.

A suitable ferrous salt is, for instance, ferrous. sulphate, which ispreferably used in aqueous solution. Other ferrous salts are, forexample, ferrous chloride, ferrous acetate, ferrous lactate.

,Alicyclic hydrocarbons, the hydroperoxides ;of{, -which may besubjected to the treatment of thei present invention and thereby yielddi-k'etones, arefor instancebut without limitation thereto. methylcyclopentane, ethyl cyclopentane, pr'opyl.

. cyclopentane, isopropyl cyclopentane, methyl c'yclohexane, ethylcyclohexane, isopropyl cyclohexane. The proportion of the components ofthe reaction may vary.

The process according to this invention ma ,be carriedout by bringingthe hydroperoxide of the said alicyclic hydrocarbons into intimatecontact with for instance, ferrous sulphate, preferably in aqueoussolution. Alternatively, the reaction may be carried out with a solutionof the hydroperoxide for instance in the unchanged 'alicyclichydrocarbon which contains only a small percentage of the hydroperoxide.Such solutions are obtained in the well known way for instance j whenthe alicyclic hydrocarbon is oxidised by means of molecular oxygen forthe preparation "of its hydroperoxide without separating the latter fromthe unchanged hydrocarbon. In this case, it is preferred to treat thehydroperoxi'decontaining reaction mixture resulting from" the oxidationprocess with water or a solution of aqueous solution. It is preferred,however, to

Accordingly the process of this invention for c to the process of thisinvention is exothermic so the production of aliphatic di-ketonescomprises carry out" the reaction in acid solution, preferably gacidified by mineral acid such as sulphuric acid. The amount of acid isconveniently such as to prevent the iron from-being precipitated. 1 Thereaction of: the hydroperoxides according out and may be recovereddirectly by filtration.-

When a" solution of the hydroperoxide in unreacted hydrocarbon such asthe crude oxidate, is

treated according to the present invention the di-ketone formed may beseparated by, forinstance, decanting the organic solution from theaqueous phase and subsequently distilling the organic solution wherebyunreacted hydrocarbon which served as a solvent, 'distils off. With thehydrocarbon any alcohols and/or mono-ketones which are present in thereaction mixture distil From the residue the di-ketone over as well.crystallises out or may be precipitated therefrom by the addition of aliquid for instance petrol ether in which the di-ketone is insoluble.

As by-products of the reaction with the ferrous salt according to theinvention, alcohols and mono-ketones are produced. In the case of methylcyclopentane hydroperoxide the ketone formed as such a by-product ismainly methylbutyl ketone. These alcohols and mono-ketones may beremoved if desired by distillation. The ferric compounds produced duringthe reaction by oxidation of the ferrous compounds may be reconverted toferrous compounds by reduction, for instance with sulphur dioxide.

The di-ketones produced according to the process of this invention maybe used for the preparation by oxidation of di-basic acids such assebacic acid, suberic acid and the like.

-The following examples illustrate the manner in which the process ofthe invention may be carried out in practice the quantities given beingparts by weight.

Example 1 parts of methyl cyclopentane hydroperoxide were shaken at roomtemperature with 100 parts of water in which 62 parts of crystallineferrous sulphate had been dissolved. The temperature of the reactionmixture rose considerably whilst a brown iron hydroxide deposit settledout. The reaction mixture after having been cooled was Example 2 '20parts of methyl cyclohexane hydroperoxide were heated on a water bathfor 3 hours with an aqueous solution containing parts of crystallineferrous sulphate. The product was ether extracted and distilled. Afraction containing ketones and alcohols was obtained, weighing 15.0

parts,- whilst 1.7 parts of a fraction consisting 1 mainly oftetradecanedione-2213 was obtained. This di-ketone is insoluble inwater, and soluble in most organic solvents. It crystallises in whiteshining leaflets with a M. P. of 76-77" C.

Example 3 10 parts of methylcyclopetane hydroperoxide (87.2% pure)dissolved in 10 parts of ethanol were added slowly with stirring to asolution of 30 parts of crystalline ferrous sulphate, '7 parts ofsulphuric acid, 32 parts of ethanol, and 70 parts of water. 4.4 parts ofdodecanedione-Zzll were obtained which was isolated by filtration.

A similar experiment in which the sulphuric acid was omitted yieldedonly 3.2 parts of dodecanedione.

. v Example 4 10 parts of methylcyclopentane hydroperoxide (95.6% pure)was converted into its sodium salt by dissolution in the calculatedquantity of 10% sodium hydroxide solution, and the aqueous solutionsoobtained was added slowly with stirring to a solution of 30 parts ofcrystalline ferrous sulphate made up to 100 parts with water. Theprecipitated iron hydroxide was dissolved by acidification, and theorganic product was isolated by extraction with ether. 2.9 parts ofdodecanedione-2:11 and 2.6 parts of a fraction consisting of alcoholsand mono-ketones were thereby obtained.

Equivalent quantities of ferrous chloride, ferrous acetate and ferrouslactate may be used in,

said ring compound.

2. A process according to claim 1 wherein the solution of the ferroussalt is an aqueous solution of ferrous sulphate.

3. A process according to claim 1 wherein the reaction is effected underacid conditions.

4. A process according to claim 1 wherein the hydroperoxide is methylcyclopentane hydroperoxide.

5. A process according to claim 1 wherein the hydroperoxide is methylcyclohexane hydroperoxide.

6. A process which comprises reacting the oxidate solution resultingfrom reacting the alkyl substituted saturated alicyclic hydrocarbon ring"selected from the group consisting of cyclopentane and cyclohexane withmolecular oxygen-to convert part of said hydrocarbon into thecorresponding hydroperoxide so that unreacted hydro- ,carbon is present,with aqueous ferrous salt solu- "tion and recovering t di-ketoneproduced thereby from its solution in the unreacted hydrocarbon.

I EDWIN GEORGE EDWARD HAWKINS.

REFERENCES CITED The following references are of record in the file ofthis patent:

Work, J. Chem. Soc., 1940 vol., pages 1307-1315.

fHock et al., Berichte, vol. 75, pages 1051-1054 (1942); vol. 76, pages1130-1131 (1943); vol. 76, pages 169-172 (1943).

1. A PROCESS WHICH COMPRISES REACTING WITH A SOLUTION OF A FERROUS SALTIN THE PRESENCE OF SOME WATER, A HYDROPEROXIDE IN THE ALKYL SUBSTITUTEDSATURATED ALICYCLIC HYDROCARBON RING SELECTED FROM THE GROUP CONSISTINGOF CYCLOPENTANE AND CYCLOHEXANE WHEREIN THE PEROXIDE GROUP IS ATTACHEDTO A TERTIARY CARBON ATOM WHICH FORMS PART OF SAID HYDROCARBON RIGN ANDIS ALSO ATTACHED TO SAID ALKYL GROUP, THE DI-KETONE PRODUCED HAVINGTWICE AS MANY CARBON ATOMS AS THE SAID RING COMPOUND.